Frequently asked questions

Where does the data come from?

From 16 datasets of RDW’s open data. We check several times a day whether a new version has been published, and process it. Each response states per dataset when RDW published it (source_published_at) and when we last checked (last_checked_at).

Is KentekenFeed a service of RDW?

No. KentekenFeed uses RDW’s open data, but is not a service of RDW.

How is this different from RDW’s open data?

RDW’s open data is free, but it sits in separate datasets with text columns in varying notations. KentekenFeed joins those datasets per registration and returns them with English field names and fixed types. We also compare every new version with the previous one, so you get the changes per registration and per field without diffing two full versions yourself. See the differences side by side.

Do I see every change to a vehicle?

You see every difference between two successive versions of the open data that we processed. RDW usually publishes a dataset daily; when a value changes more than once between two versions, you see only the result. A change is in the feed after RDW has published it and we have processed the new version, not at the moment something happened in the real world.

Can I try KentekenFeed for free?

The demo on the home page works without an account, and creating an account is free. For API requests with a key of your own you need a plan or pay as you go, which you activate in the portal with a payment method. Pay as you go has no fixed fee; what is included per month and what a lookup costs after that is listed with the plans and prices.

What happens when my allowance runs out?

Above the included number of lookups you pay per extra lookup, up to the maximum of your plan. Once that maximum is reached, the API answers 429 usage_cap_reached until the next calendar month starts. Analytics queries stop at their own maximum with 429 query_cap_reached. The numbers and prices are in the comparison of the plans. If you expect more than the largest plan allows, discuss your volumes with us.

What is the difference between a snapshot and a mutation file?

A snapshot is the whole register at one moment, as files per dataset: it is how you start a copy of your own. A mutation file holds only the changes of one day or between two cursors, the same records as the feed: it is how you keep that copy current. The page about the mutation feed and snapshots explains how.

Does it contain owner details?

No. RDW’s open data has no names or addresses of owners or keepers, so neither does KentekenFeed.

What counts as a lookup?

Every successful response to GET /vehicles/{registration}, including those served from our cache. Invalid and unknown registrations, refused requests and outages don’t count. A request you repeat counts again.

What if a dataset is out of date?

You still get the data, with stale: true on that dataset. It is there in two cases. We have not been able to check for more than 36 hours whether RDW published a new version: last_checked_at shows when that last succeeded. Or we found a newer version that we are still processing: until that is done, you get the version before it. When one dataset in a response is stale, the response as a whole says stale: true too. That way you decide what to do with it.

What do appeared and disappeared mean?

That a row was added to or removed from RDW’s open dataset. They are not registration or deregistration events: RDW publishes no time per change. Dates such as registration_date are in the change itself.

Can I use several API keys?

Yes, for example one per application, each with only the access it needs. You create and replace keys in the portal. When you replace a key, the old one can keep working for up to 7 days.